The subject application relates generally to the field of radar signal processing, and more particularly to an approach to generating and utilizing look-up tables for determining an angle of arrival of a radar signal received from an emitter.
Angle of Arrival (AoA) determination requires an accurate description of the antenna performance over azimuth or elevation angle while avoiding ambiguity. Currently, the standard industry practice is to curve fit the antenna radiation pattern. One criterion by which radar receivers, such as Radar Warning Receivers (RWR), are evaluated is the Root Mean Square (RMS) angular error, which is principally determined by the quality of the radiation pattern and the curve fit.
U.S. patent application Ser. No. 13/958,240 (published as U.S. Publication No. 2015/0035696), entitled “Optimized Monotonic Radiation Pattern Fit with Ambiguity Resolution” and filed Aug. 2, 2013 describes systems and methods for characterizing a radiation pattern of an antenna to improve the determination of an angle of arrival of a radar signal received by the antenna. In particular, U.S. patent application Ser. No. 13/958,240 features an optimized monotonic fitting approach to characterizing the radiation pattern. As disclosed therein, an approximation of the radiation pattern is represented as a window map having a plurality of windows. An optimized monotonic fit of the radiation pattern is determined by adjusting the window map, one window at a time, and testing the resulting new approximations. U.S. patent application Ser. No. 13/956,240 tangentially relates to example embodiments of the subject application and the entire contents thereof are hereby incorporated herein by reference.
U.S. Pat. No. 6,657,596, entitled “Method of Measuring a Pattern of Electromagnetic Radiation” and issued Dec. 2, 2003, describes systems and methods for measuring electromagnetic radiation patterns for antennas. U.S. Pat. No. 6,657,596 provides useful background information relating to measuring and characterizing antenna patterns and the entire contents thereof are hereby incorporated herein by reference.
RWR systems, e.g., such as described in U.S. patent application Ser. No. 13/958,240, require extensive analysis in order to validate system performance. System performance validation often includes evaluation of antennas, cables, microcircuits, receivers, and other signal sensors when installed on aircraft platforms and when uninstalled. Furthermore, performance needs to be assessed within hostile environments (hot, cold, vibrations, etc.). Typically, validation may include the evaluation of system “amplitude difference lookup tables,” AoA, aircraft structure sensor interference, accuracy predictions, error identification, calibration processes, and other similar criteria.
Validation analyses are often not conjoined and typically require considerable time investment, and are not cost effective. Typically, the analysis of antenna radiation performance data is performed manually and occasionally with the aid of statistical tools. For example, an analyst may evaluate individual antenna radiation pattern plots for correct isotropic gain levels, beamwidth, and beam squint. This can involve several parallel manual analyses, such as effective antenna aperture gain predictions. Another example analysis is AoA calculation. Unfortunately, conventional AoA evaluations are not associated with other comparative analyses and therefore may often result in AoA calculation errors. Unreliable equipment setup and/or testing apparatus may also result in additional AoA calculation error. Furthermore, current practice is to limit frequency and polarization analyses by compensating with interpolation and extrapolation resulting in less accurate performance representation.
Thus traditional validation and evaluation methods are time consuming and prone to inaccurate determination. Under the conventional methods, it is often not possible to meet customer schedule when thousands of performance characterizations are required. Moreover, these methods fail to make use of High Power Computing (HPC) with distributive techniques. Conventional evaluation methods are also not able to perform comparative analyses in order to select the most useful solution.
Under conventional systems and methods, suboptimal antenna field of view radiation pattern performance may result from various inaccuracies such as measurement and calculation errors. Accordingly, systems and methods are needed in order to yield optimal antenna patterns.